1. Technical Field
The present invention relates generally to broadcast signal transceiving technology, and more particularly, to broadcast signal transceiving technology to which Layered Division Multiplexing is applied.
2. Description of the Related Art
In terrestrial broadcasting, a Single Frequency Network (SFN) has emerged as an alternative to traditional Multiple Frequency Network (MFN) modes. Through the SFN, multiple transmitters simultaneously transmit signals through the same Radio Frequency (RF) channel.
The SFN provides not only a homogeneous distribution of received signal strengths over a coverage area, but also extended-coverage spectral efficiency. However, some areas may suffer signal degradation. The amplitudes of Digital Terrestrial Television (DTT) echoes, which reach a receiver with different phases despite having similar signal magnitudes, cause serious multipath conditions creating destructive interference.
In order to prevent such undesired situations, new features, such as a Multiple-Input Single-Output (MISO) scheme, have been applied to new DTT generation.
MISO denotes a radio link which uses at least two transmitters and one receiver. A conventional topology composed of one transmitter and one receiver is referred to as a Single-Input Single-Output (SISO) scheme. MISO improves the robustness of terrestrial transmission using the spatial diversity of multiple antennas. Moreover, when at least two antennas are provided in a single receiver or when two receivers collaborate with each other (e.g. Multiple-Input Multiple-Output (MIMO) antenna scheme), spatial multiplexing gain may be obtained.
In order to simultaneously support various multiple services, multiplexing, which is a procedure for combining multiple signals, is required. Among these multiple techniques, Layered Division Multiplexing (LDM) technology for combining signals in two layers by differently setting the powers of respective layer signals has been introduced. LDM has been applied to next-generation broadcasting service, such as that of Advanced Television Systems Committee (ATSC) 3.0, by providing flexibility and performance better than those of Time Division Multiplexing (TDM) and Frequency Division Multiplexing (FDM), and application fields thereof have gradually increased and diversified.
Therefore, there is urgently required the development of a new broadcast signal transceiving technique in which LDM is combined with MISO or MIMO.